While some locations in the West, such as Boulder CO, received a foot of snow this past Wednesday others are now in the grips of conditions ripe for wildfire and indeed facing outbreaks already. California is currently bearing the brunt of early-season activity with wildfires in areas in the northern part of the state and around Los Angeles. Dry, windy conditions are providing ideal conditions for these to continue growing and become less and less manageable. Officials have started evacuations in some of these areas underscoring the growing risk. Loss of life and homes are typically the paramount concerns, but fires can also have substantial air quality impacts, as well, that reach well beyond the fire borders. Perhaps even less apparent are the impacts from fires that extend well past the time the fire has been contained or put out. These include the changes to the soil character and forest ecosystems overall that substantially increase ongoing flood risk, such as that from the Waldo Canyon fire in Colorado last year. The outlook for this season says California and portions of the Southwest and Pacific Northwest are only getting a first glimpse of what may be heading their way.

Monthly wildfire outlook

This week as fires were springing up and growing in size and impacts the National Interagency Fire Center released their monthly fire outlook that covers the bulk of the summer fire season. When looking at the maps of fire potential, the eye is immediately drawn to the growing field of red spreading throughout virtually all portions California and up into Oregon and Idaho. Likewise, much of New Mexico and portions of Arizona will see increasing fire risk for the next few months pulling in portions of southern Colorado.

A growing field of red represents above normal fire potential for most of California, Oregon, and portions of Idaho in the heart of summer wildfire season. A possible bright spot is that portions of the Southwest will be returning to normal during this time after being elevated. Source: Predictive Services/National Interagency Fire Center

What is driving wildfires?

Basically, we can look to precipitation (or lack thereof) to get a top-line idea of what’s driving the activity both current and forecasted for the rest of the summer. Over the past month, virtually all portions of the West that are experiencing fire or elevated fire risk are some shade of red, meaning below average precipitation. Areas in Southern California dealing with fire outbreak saw less than 2 percent of normal precipitation. And recently New Mexico rose to the top of the ranks of drought-stricken states with much of the West under severe, extreme, or exceptional drought conditions. Sadly, there is no relief in sight as we get into the depths of the summer fire season as drought conditions are expected to persist through July for most of the West, in part driving the forecasted heightened fire risk.

A central driver of wildfire risk is drought conditions. There appears to be no relief in sight for much of the West with drought persisting over much of the region or developing in a few pockets in the Southwest and in Northern California and Oregon. Source: NOAA

Many factors play a role in fire risk and outbreak. How much fuel is available which can touch upon past land management practices and perhaps disturbances such as insect outbreaks and tree mortality. There is always an ignition risk from either lightning strikes or a campfire that was not fully put out. But dry fuels (trees, brush, and duff) represent a major risk factor. And the continuing widespread drought has both been priming current conditions and will likely continue to do so throughout not only this season, but further down the road as well.

Fire has always been a part of the West. For those of us who live or have lived there it is part of the trade-off for endless big sky vistas and majestic mountain landscapes. But it appears that it is an impact that is growing as the number of fires and area burned have increased over the past few decades and the fire season has lengthened. At the same time spring and summer temperatures have increased along with earlier spring snowpack melt overall and are likely driving increasing fire risk. Naturally, questions arise as to whether response plans are and will continue to be sufficient, how will sequestration and shrinking budgets affect things, what actions are local cities and towns taking to help reduce risk, and what does the future hold for wildfire in a warming climate. We’ll have to leave the answers for another post.

About the author:
Todd Sanford is a climate scientist with expertise in the atmospheric chemistry and physics of the climate system. His current work involves the public health impacts of climate change. He holds a PhD in physical chemistry from the University of Colorado. See Todd's full bio.

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